This invention deals with oxidation of organic compounds using a perfluorocarbon polymer oxidation catalyst consisting of a perfluorocarbon main chain and a side chain constructed from structural units of chromium (III) difluoromethylene sulfonate or cerium (IV) difluoromethylene sulfonate, and particularly a method of preparing organic carbonyl compounds by oxidation of an alcohol in the presence of the aforementioned catalyst.
The oxidation of alcohols to produce carbonyl compounds such as aldehydes, carboxylic acids and ketones has been used in industry and laboratories alike. Since this oxidation does not proceed well with an organic peroxide, it is normally carried out in the presence of an inorganic oxidizing agent with a strong oxidizing power such as chromium (VI). One of the problems of using chromium (VI) as the oxidizing agent for the oxidation of an alcohol is the fact that it produces a rubbery precipitate. Another problem of using chromium (VI) as the oxidizing agent is the fact that the aldehyde, carboxylic acid or ketone formed cannot be separated from each other without difficulty, which results in lower yields of the desired products. Furthermore, the oxidation uses at least the chemical stoichiometric amount of chromium (VI), which means that a large amount of expensive and toxic chromium (VI) is involved in the process. This is a serious problem economically and also from the standpoint of industrial waste.
J. M. S. Frechet et. al. reported that poly (vinylpyridinium chlorochromate) can be used as the oxidizing agent for the alcohol. (Journal of Organic Chemistry, 43, 2618 (1978).) Although this method successfully prevented the formation of the rubbery precipitate, it had problems. For example, the exchange capacity of poly(vinyl pyridinium chlorochromate) was low and a large amount of polyvinyl pyridinium had to be used. When polyvinyl pyridinium was used as an oxidizing agent, the compound deteriorated and it was difficult to reuse the compound. Even when the compound could be reused, the oxidation reduced the chromium to (III) or (IV) and it had to be ion exchanged with chromium (VI) before it could be used again.